Question

There are 24 students in a science class. Mr. Sato will give each pair of students 3 magnets. So far, Mr. Sato has given 9 pairs of students their 3 magnets. How many more magnets does Mr. Sato need so that each pair of students has exactly 3 magnets?

Answer 1

3×(24÷2)-3×9

Answer is 9

Explanation:

3×(24÷2)-3×9

Basically it is #magnets given to pairs x (total # pairs) - 3 magnets per pair x 9 pairs already given magnets. For solving, visualizing purposes only (do not write it out like this): [3x(24÷2)] - [3x9] = x. You are solving for total magnets to be handed out minus the total magnets already handed out. Final answer is 9 magnets are needed.

Answer 2

3x (x=students)
3(24)=72
He has given 9 students their magnets so 9(3)=27
72-27=45
He needs 45 more magnets